Email a friend

To

From

Thank you

Your message has been sent.

Sorry

There was an error emailing this page.

11 sure signs you've been hacked

FREE

Become An Insider

Sign up now and get free access to
hundreds of Insider articles, guides, reviews, interviews, blogs, and other premium content
from the best tech brands on the Internet: CIO, CSO, Computerworld, InfoWorld,
IT World and Network World Learn more.

In today's threatscape, antivirus software provides little piece of mind. In fact, antimalware scanners on the whole are horrifically inaccurate, especially with exploits less than 24 hours old. After all, malicious hackers and malware can change their tactics at will. Swap a few bytes around, and a previously recognized malware program becomes unrecognizable.

To combat this, many antimalware programs monitor program behaviors, often called heuristics, to catch previously unrecognized malware. Other programs use virtualized environments, system monitoring, network traffic detection, and all of the above at once in order to be more accurate. And still they fail us on a regular basis.

Here are 11 sure signs you've been hacked and what to do in the event of compromise. Note that in all cases, the No. 1 recommendation is to completely restore your system to a known good state before proceeding. In the early days, this meant formatting the computer and restoring all programs and data. Today, depending on your operating system, it might simply mean clicking on a Restore button. Either way, a compromised computer can never be fully trusted again. The recovery steps listed in each category below are the recommendations to follow if you don't want to do a full restore -- but again, a full restore is always a better option, risk-wise.